Telecentric Image Display Optics for Compact Mid-Air Projection
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Solution Overview
Problem
Existing image display devices are large and struggle to provide high-quality images in a compact form, particularly in vehicular applications where space is limited, and they often require complex optical systems to achieve desired image projections.
Innovation Solution
The image display device incorporates a light source unit with a telecentric imaging optical system and a reflection unit that separates the light source from the image-forming element, allowing for the formation of real and virtual images, including mid-air images, using a combination of LEDs and optical elements like mirrors and dihedral corner reflectors to achieve compactness and high image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a compact imaging optical system is used, then the device size is reduced, but image quality may deteriorate
Solution Approach 1:
The imaging optical system is divided into multiple independent optical elements (first optical element, second optical element, third optical element) that can be separately designed and optimized. Each element handles specific portions of the optical path, allowing for compact overall design while maintaining image quality through specialized optimization of each segment.
Solution Approach 2:
The patent employs a nested arrangement where the real image is formed within the optical path between the display device and the combiner, and the virtual image is subsequently formed by reflecting this real image. This nesting of image formation stages allows compact packaging of multiple imaging functions in a small volume while preserving image quality through proper optical design of each stage.
2Manufacturing precision
If multiple optical elements are used to form real and virtual images, then image quality is improved, but device complexity increases
Solution Approach 1:
The imaging optical system is designed so that the same optical elements (first, second, and third optical elements) perform multiple functions: forming the real image, directing light to the combiner, and enabling virtual image formation. This multi-functionality reduces the total number of separate components needed while maintaining high image quality through careful design of each element's dual or triple roles.
Solution Approach 2:
The patent combines the functions of real image formation and virtual image formation into a single integrated optical path. The light from the display device passes through multiple optical elements that simultaneously create the real image and direct it to the combiner for virtual image formation, merging what could be separate systems into one unified compact structure.
3Volume of moving object
If the light source unit is compacted, then device size is reduced, but light distribution control becomes more difficult
Solution Approach 1:
Each optical element in the compact imaging system is designed with specific local optical properties tailored to its position and function. The first optical element has different characteristics than the second and third elements, with each optimized for its specific role in the light path. This local optimization allows effective light distribution control in a compact configuration where uniform design approaches would fail.
Solution Approach 2:
The optical system is designed to dynamically control light distribution through the sequential action of multiple optical elements. Each element can be independently optimized to handle specific light angles and distributions, allowing the compact system to maintain effective light control by adapting the optical path through the series of elements rather than requiring a single large controllable component.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables the creation of high-quality, compact image display systems that can project real and virtual images, including mid-air images, effectively utilizing space in vehicles while maintaining image clarity and reducing the size of the light source unit, allowing for simultaneous viewing of virtual and mid-air images by the user.
Implementation Method 1
The imaging optical system includes an input element on which light emitted from the first display device is incident, and an output element on which light traveling via the input element is incident; light emitted from the output element forms a real image corresponding to the first image
Implementation Method 2
the reflection unit is separated from the light source unit and reflects light emitted from the imaging optical system
Implementation Method 3
the image-forming element displays the second image in mid-air based on light emitted from the second display device
Data Source
AI summary
An image display device includes: a light source unit including: a first display device configured to emit light having a substantially Lambertian light distribution and to display a first image, and an imaging optical system including: an input element on which light emitted from the first display device is incident, and an output element on which light traveling via the input element is incident, the output element being configured to emit light that forms a real image corresponding to the first image; a reflection unit separated from the light source unit, the reflection unit configured to reflect light emitted from the imaging optical system; a second display device configured to display a second image; and an image-forming element configured to display the second image in mid-air based on light emitted from the second display device. The imaging optical system is substantially telecentric at the real image side.